The mutant prevention concentration (MPC) is defined as the lowest antimicrobial concentration required to inhibit the growth of the least susceptible bacterial cell based on an inoculum of ≥109 colony forming units (CFUs). The current protocol for MPC testing is technically demanding and time-consuming which limits its implementation into clinical microbiology laboratories. In an attempt to simplify the current MPC protocol we developed a modified MPC method, the microbroth dilution method, which requires two fewer days to complete than the current or traditional method. MPC values were consistent for all organisms and strains tested using both the traditional MPC method and the modified microbroth dilution MPC method.<p> Tigecycline is the first of a new class of compound glycylcyclines- with potent in vitro activity against Gram-positive organisms including penicillin-resistant and multi-drug resistant <i>Streptococcus pneumoniae</i> (SP) and methicillin-resistant <i>Staphylococcus aureus</i> (MRSA). We measured minimum inhibitory concentration (MIC) and MPC values for tigecycline against 47 clinical isolates of SP and found that the MPC90 values were >500 fold higher than the MIC90 values. To determine if MPC testing of tigecycline against SP is impacted by blood in the medium, we developed a new medium able to sustain the growth of SP without the need for blood; solidified Todd-Hewitt broth (sTHB). The MPC90 values of tigecycline against SP on sTHB were only 2 fold higher than the MIC90 values. When blood was added to the sTHB, the MPC90 values again became much greater than the MIC90 values (> 256 fold higher). MPC results for <i>Staphylococcus spp.</i> against tigecycline were not impacted by blood in the medium.<p> Benzalkonium chloride (BAK) is a cationic surface-acting agent that acts on bacterial cells by disrupting the intermolecular interaction of the lipid bilayer. To determine if the <i>fluoroquinolones gatifloxacin</i> (Gfx) and moxifloxacin (Mfx) are more active (lower MIC values) in the presence of BAK, we conducted MIC, MPC, and time-kill assays. MIC testing showed that in the presence of 3.125 to 50 µg/ml of BAK, the MIC of Gfx and Mfx decreased by 8- to 5000-fold against clinical isolates of methicillin-susceptible <i>Staphylococcus aureus</i> (MSSA), MRSA, Coagulase-negative <i>Staphylococci</i>(CNS), SP, <i>Escherichia coli</i> (EC), and <i>Pseudomonas aeruginosa</i> (PA). MPC testing showed that the presence of 7 to 10 µg/ml of BAK, the MPC of Gfx and Mfx decreased by 32- to 1000-fold against clinical isolates of MRSA. Conventional time-kill studies (using a bacterial load of 105 CFUs) showed that the killing activity of Gfx against clinical MRSA isolates was enhanced in the presence of BAK with a log10-reduction (percent kill) of 1.6 (76.08%) for Gfx alone at 180 minutes compared to a log10-redecution (percent kill) of 5.4 (100%) for Gfx plus BAK at 180 minutes.<p> Alexidine (Alx) is a bisbiguanide that has been used as an effective disinfectant in the dental industry and is potentially being developed for use as an antimicrobial agent for ocular infections. We conducted susceptibility testing of Alx using MIC testing, MPC testing, and time-kill assays against Gram-positive and Gram-negative pathogens. MIC testing showed that Alx is more active against Gram-positive pathogens than Gram-negative pathogens and showed better activity than the fluoroquinolones Gfx, Mfx, and levofloxacin (Lfx) against MRSA. The MPC values measured for MRSA and MSSA against Alx were non-reproducible using the traditional MPC method. Using the microbroth dilution MPC method, MPC90 values were found to be 32 fold higher than the MIC90 values. If the experimentally determined MPC values are true MPC values, initial MPC testing indicates that Alx may have a high likelihood for selecting for resistance, however, if the MPC values are not accurate it may be necessary to modify the MPC protocol in order to complete MPC testing of Alx against MRSA and MSSA. Conventional time-kill studies (using a bacterial load of 105 CFUs) measured bactericidal activity (> 3 log10-reduction) against MRSA, MSSA, SP, and PA.

The U.S. trucking industry was deregulated with implementation of the Motor Carrier Act of 1980. After deregulation, increased concentration was observed in the general freight segment of the industry. The purpose of this study was to examine structural differences in general freight commodity carriers and to help explain the increased concentration. Cost functions were estimated for large and small carriers in order to see whether or not size related advantages exist. Although the hypothesis of constant returns to scale could not be rejected, significant structural differences were found between large and small carriers. The results imply that the services provided by large and small carriers are different. Presence of "economies of integration and "economies of route density" for large firms indicate the possibility of oligopoly in the general freight commodity trucking. / Graduation date: 1992

Ce mémoire porte sur l'Observatoire international des médias (OIM), association dont nous explorons et analysons le siège social, à savoir l'Observatoire français des médias (OFM), à travers le spectre de la manipulation médiatique et de l'opinion publique, concept entendu en termes d'action civique au sein d'une sphère démocratique. Pour commencer, nous traçons un portrait succinct de l'industrie médiatique actuelle, avec laquelle nous nous sommes familiarisé pendant notre recherche et durant notre cheminement au cours de la maîtrise en communication. Ensuite, nous présentons les deux concepts clés qui délimiteront le cadre théorique de notre travail, notamment la manipulation médiatique et l'opinion publique. Nous exposons dès lors le projet du Monde diplomatique, à savoir, l'OlM, qui fut conçu pour inciter les citoyens à participer activement à la vie publique et démocratique, en les invitant à démasquer les distorsions et les disparités issues des firmes médiatiques de l'industrie des communications. Nous visons plus précisément l'étude du potentiel de l'OFM (puisque ce dernier est sous le patronage l'OIM et qu'il en est la première expression) en termes d'efficacité, de rendement et de participation citoyenne, tout en considérant les balises de notre cadre théorique. D'un côté, nos hypothèses argueront qu'un projet tel que l'OFM ne répond pas effectivement au problème de la manipulation médiatique comme elle est définie par un grand nombre de penseurs que nous visiterons, et d'un autre côté, nous présageons un faible engagement citoyen quant à l'action civique prévue par l'observatoire. Dans notre cadre théorique, nous traçons un historique de la pensée critique en termes d'opinion publique, puis nous considérons les thèses des auteurs critiques contemporains au sujet de la manipulation médiatique. Par ailleurs, en vue de confirmer ou d'infirmer nos hypothèses, nous nous basons principalement sur le site Web de l'OFM, pour en faire une analyse de contenu qualitative. Ainsi nous nous enquérons sur les fondements de l'observatoire, ses activités, ses projets et les indicateurs de participation citoyenne quand à ses plans d'action. Nous concluons que l'OFM répète, quoi qu'à une moindre échelle, les mêmes schémas d'endoctrinement, de matraquage et de persuasion que les médias qu'il critique, et que la participation citoyenne à ses activités (réduites) reste relativement restreinte. De ce fait, nous confirmons que ce projet de mobilisation civique ne recueille qu'une participation élitaire et qu'il n'est, en effet, qu'une fausse solution à un vrai problème. Ainsi, dans nos sociétés d'informations modernes centrées autour des médias, nous achevons en témoignant que le doute est la meilleure attitude dont les citoyens devraient se doter en vue de chercher à être bien informés. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : Observatoire international des médias, Observatoire français des médias, Manipulation médiatique, Mésinformation, Journalisme, Concentration, Concurrence, Opinion publique et Espace public.

The purpose of the study is to examine different situations and behaviors for students diagnosed with AD / HD and see if there are times where their diagnosis will be extra visible. This will ultimately see how and where these children may need support in their daily lives, and about the support they receive is relevant to their needs. Questions I intend to examine: Are there situations for students throughout the school day in which ADHD diagnosis becomes extra visible? If so, what situations? How is the diagnosis in these situations? It is estimated that about 3-6 percent of school children have AD/HD. It causes difficulties with concentration as well as impulse and activity control. It's not a given that these students get the right support. This is a qualitative study using observations of two children to investigate whether there are situations where students' AD/HD will be extra visible. The results show that there are times when these behaviors clearly manifests during the school day, but also that there are some occasions when some behavior is not particularly noticeable. Some behaviors became evident during the free time during the day, while others became more visible during the controlled period. The result also shows that the times when behaviors are apparent, differs between the two observed the students. This emphasizes the importance to look to the specific needs of support for each individual.

In this project a method based on surface plasmon resonance has been developed for determining the concentration of several His-tagged proteins in complex solutions. It showed large dynamic range, no measureable non-specific binding and high sensitivity (with linear range around 0.1–10 μg/ml depending on the proteins). The method showed a low variation when checked on MBP-His during an extended time period. The concentrations of the His-tagged protein in the lysate has also been determined and compared with other alternative methods. This method will later be used to analyse protein concentrations during development and optimization of chromatographic purification process.

The aim of this project was to explore the shapes of dark matter halos using high resolution N-body simulations. One of the main aspects explored was how well the shape can be measured through weak lensing. To explore this, simulations were run using the GADGET-2 code \cite{SPRING05} and a method used to measure ellipticities was tested \cite{oguri1}. It was found that Large Scale Structure along the line of sight diluted the measurements and made halos appear more spherical. On the other hand, substructure close to the halo introduced a bias where intrinsically elliptical halos appeared to be slightly more spherical and intrinsically spherical halos appeared to be slightly more elliptical. The effects of projection on concentration were also explored, it was concluded that halos which are most elliptical in 3D tend to appear the most concentrated in projection. Finally, we tested the possibility of using shape or concentration measurements to help break the degeneracy in $\Omega_M$ and $\sigma_8$. We found that this may be possible with $\sim$ 3000-4000 shape measurements or $\sim$ 400-500 concentration measurements.

The mutant-prevention concentration (MPC) is a novel susceptibility measurement defined by a concentration threshold that would require cells to contain two concurrent resistance mutations for growth. Pneuococcal pneumonia, infections caused by <i> Pseudomonas aeruginosa</i>, and urinary tract infections caused by Gram-negative bacilli represent three distinct clinical situations for which fluoroquinolone-resistance occurs. MPC results were defined and measured for fluoroquinolones against clinical isolates of <i>Citrobacter freundii, Enterobacter cloacae, Escherichia. coli, Klebsiella pneumoniae, P. aeruginosa,</i> and <i> Streptococus pneumoniae</i>. Against clinical isolates of <i>S. pneumoniae</i>, MPC results for six fluoroquinolones were measured. Based on their potential for restricting the selection of resistant mutants, the six fluoroquinolones, in descending order, were found to be gemifloxacin > moxifloxacin > trovafloxacin > gatifloxacin > grepafloxacin > levofloxacin. For several compounds, 90% of clinical isolates that lacked a known resistance mutation had a MPC value that was close to or below the serum levels that could be attained with a dosing regimen recommended by the manufacturers. These data identify gemifloxacin, moxifloxacin and gatifloxacin as good candidates for determining whether MPC can be used as a guide for choosing and eventually administering fluoroquinolones to significantly reduce the development of fluoroquinolone ¡Vresistant <i>S. pneumoniae</i>. MPC90 results for 155 clinical isolates of <i>P. aeruginosa </i>against ciprofloxacin and levofloxacin were 4 and 16 Ýg/ml, respectively. Serum drug concentrations reported previously for standard doses were above MPC90 for 5.5 hr for ciprofloxacin and 0 hr for levofloxacin. These data suggest that superior clinical performance of ciprofloxacin correlates with activity against resistant mutant subpopulations measured in vitro. MPC results were compared with minimum inhibitory concentrations (MIC) measurements preformed by agar dilution, and microbroth dilution and minimal inhibitory concentrations (MBC) for 100 clinical isolates of <i>C. freundii </i> (n=20), <i>E. cloacae</i> (n=20), <i>E. coli</i> (n=20), <i>K. pneumoniae</i> (n=20), and <i>P. aeruginosa</i> (n=20) for ciprofloxacin, levofloxacin and garenoxacin. MPC results were 2-to-8 fold higher than MIC or MBC results. Ciprofloxacin MPC results for <i>E.coli, C. freundii, E. cloacae, K. pneumoniae</i>, and <i>P. aeruginosa</i> were 0.5, 2, 1, 1, and 4 Ýg/ml, respectively. Levofloxacin, MPC results were were 1, 2, 4, 1, and 16 Ýg/ml, respectively. Garenoxacin, MPC were 1, 8, >8, 4, and >32 Ýg/ml, respectively. Garenoxacin had the highest MIC and MPC results and was the least active compound tested against isolates of <i>C. freundii, E. cloacae</i>, and <i>P. aeruginosa</i>. These data support the rational use of quinolones in the treatments of urinary tract infections and suppression of resistance. Incorporation of the MPC measurement into dosing strategies may preserve the longevity of antimicrobial compounds for future infectious diseases.

Dietary energy is the largest single cost in pork production. Accurate and current understanding of energy metabolism is crucial to production efficiency. The overall objective of this thesis was to evaluate the effects of dietary energy concentration and energy intake on growth, nutrient deposition rates and energy utilization in weaned pigs. In experiment 1, the optimum total lysine:DE ratio for weaned pigs was estimated at 4.27 and 4.46 g/Mcal for pigs growing from 7.5 to 12.8 kg and 7.5 to 22.5 kg BW, respectively. Experiment 2 determined if a more predictable growth, nutrient deposition and energy utilization in the weaned pig is achieved with NE or with DE. ADG either remained similar or was depressed with increased NE compared to the control (P < 0.05). Empty body protein content and deposition (PD) declined relative to the control (P < 0.05) and lipid content and deposition (LD) tended to increase (P < 0.10). Body composition and nutrient deposition rates were more correlated with determined NE concentration and intake compared with DE. The results of Experiment 3 indicated that amino acid intake impaired the growth of pigs when an energy intake restriction greater than 30% occurred. Experiment 4 investigated the interaction of dietary NE concentration and feeding levels (FL) on body weight gain, tissue (protein, lipid, ash, water) accretion rates and ratios. Growth performance was not affected by NE (P > 0.05) but increased with feeding level (P < 0.001). Energy intake increased with NE and FL (P < 0.001), but the efficiency of energy utilization for growth declined (P < 0.05). Empty body protein content declined (P < 0.05) while lipid content increased with NE (interaction, P < 0.05). Empty body PD was not affected by NE (P > 0.05) but both LD and LD:PD ratio increased (interaction, P < 0.001). These data suggest that when amino acid:energy ratio is optimal, increasing dietary energy concentration increased energy intake but does not improve PD and overall body weight gain of weaned pigs. However, body lipid content and LD were increased. Finally, NE offers an advantage over the DE in predicting the body composition and nutrient deposition rates rather than in overall BW gain.

In Canada, flax (<i>Linum usitatissimum</i> L.) is grown for its seed oil. However, a major disadvantage associated with growing oilseed flax is that the straw is difficult to incorporate into the soil after harvest. Instead, the majority of flax straw is burned in the field, increasing the workload for farmers, as well as creating air pollution. Agronomic concerns are also associated with burning, since it leaves fields vulnerable to wind and water erosion. A small market exists for Canadian flax straw for making high quality paper products and some plastic composites. However, fibre-based and fibre-using industries are growing world wide, and flax straw fibre is becoming an important product. Flax straw fibre concentration varies among cultivars and environments. Consistently high fibre concentrations are essential if the fibre in oilseed flax is to become an important product for Canadian farmers. This study assembled the agronomic information necessary to select for increased straw fibre concentration in the Crop Development Centre (CDC) Flax Breeding Program. Three experiments were conducted to determine: how seeding rate and row spacing effects straw fibre concentration, the effects of seeding date on straw fibre concentration, and how nitrogen fertilizer rates effects straw fibre concentration. Seeding in mid-May at either an 18 or 36 cm row spacing at a seeding rate of 30 or 45 kg/ha resulted in high straw fibre concentration without reducing other important oilseed characteristics such as seed yield, oil content and straw fibre yield. Nitrogen fertilizer did not have an effect on either straw fibre concentration or straw fibre yield.

Oilseeds may be processed to yield a number of potentially valuable compounds and fractions including oil, protein and small molecules. However, energy costs associated with industrial processing of oilseeds can be significant. For example, processes that use water to dissolve and separate materials are burdened with the costs associated with concentrating value-added products from dilute solutions. The ethanol industry produces large amounts of an aqueous solution called thin stillage that has little value and is used in animal feed. Thin stillage contains some of the necessary salts used in protein extraction but has a low pH. Protein extraction and protein isolate production is commonly conducted at higher pH. Waste alkali from biodiesel production has a high pH and can be used to adjust the pH of thin stillage to improve its ability to extract protein from oilseed meal. By combining the properties of the waste products of both the ethanol and the biodiesel industries, a complementary process is possible that may have greater economic potential than current practices in industry.<p> In this study, processes for protein extraction from mustard (<i>Brassica juncea</i> (L.) Czern.) meal using thin stillage from ethanol production and glycerol from biodiesel production were studied. The osmotic potential of thin stillage used in this research was lower than that of water, whereas both the density and the viscosity were higher. The pH was typically 3.7-3.8, and the total Kjeldahl nitrogen was approximately 0.080.10 %, w/w. Organic compounds identified in thin stillage were isopropanol, ethanol, lactic acid, 1,3-propanediol, acetic acid, succinic acid, glycerophosphorylcholine, betaine, glycerol and phenethyl alcohol. In addition, yeasts, bacteria and fungi were also found. Moreover, the salt types and their concentrations in thin stillage were predictable. The salt types present in thin stillage were CaCl2, NaCl, K2SO4, NaNO3, Mg(OH)2, Na2SO4 and KOH. A model thin stillage synthesized for the purposes of this research had components and chemical and physical properties comparable to those of thin stillage from ethanol production. Protein was extracted from ground, defatted meal using thin stillage at different pHs and salt concentrations. The results showed that pH and salt content affected protein extraction efficiency. However, no differences were found in the efficiency of extraction, SDS-PAGE profile, digestibility, lysine availability or amino acid composition of protein extracted with thin stillage, model thin stillage or sodium chloride solution. Moreover, extracted protein did not display significant hydrolysis. The results from peptide sequencing showed that napin and cruciferin were the most prevalent proteins in the extracted fractions. When increasing the scale of the extraction, the efficiency of protein extraction and the percentage of protein in the extracted protein were decreased. Protein recovery achieved with the complementary protocol was higher than that reported for a published protocol. Allyl isothiocyanate was found in protein extracts.